I had a hard disk failure recently. I decieded to install a new 500GB hard disk. I have windows 7 original version pre installed in my lap. When i bought a new hard disk i cannot install my registered version of Windows 7. When installing using the recovery disk i was bought a error message that the drive cannot be formatted. Can i download a windows 7 home premium edition and does my serial number work with that OS or i have to purchase a new license.